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The present invention relates to the general field of telephone communications. In more particular, the invention relates to systems to assist telephone communications by those persons who are deaf, hard of hearing, or otherwise have impaired hearing capability.
Most modern human communications in both social and business environments takes place through sound communications. Yet within modern society there are many persons who have attenuated hearing capability. To assist those persons in making use of our telephonic communication system built for the hearing majority, there has been developed a system of telephone communication which has been principally used by the deaf community. That system makes use of a category of device known variously as a telecommunication device for the deaf (TDD), text telephone (TT) or teletype (TTY). Current TDDs are electronic devices consisting of a keyboard and a display as well as a specific type of modem, to acoustically or directly couple to the telephone line. Modern TDDs permit the user to type characters into their keyboard, with the character strings then encoded and transmitted over the telephone line to be displayed on the display of a communicating or remote TDD device.
Most TDD communication is conducted in an idiosyncratic code specific to the community of TDD users. This code, known as Baudot, evolved historically at a time when many telecommunication devices for the deaf were based on mechanical or electromechanical devices rather than the current technology based on digital electronic components. Accordingly, the Baudot protocol was constructed for a set of constraints which are no longer relevant to present date devices. The original Baudot protocol was a unidirectional or simplex system of communication conducted at 45.5 Baud. The conventional Baudot character set was a character set consisting of 5 bit characters and the system encodes the bits of those characters in a two-tonal system based on carrier tones of 1400 and 1800 Hertz.
The system of TDD communications is widely used and in fact has become indispensable to the deaf community throughout the industrialized world. Deaf persons extensively communicate with their neighbors and with other deaf and hearing people remotely, using the TDD system. In addition, systems have been developed to facilitate the exchange of communication between the deaf community and hearing users who do not have access to or utilize a TDD device. In the United States, telephone companies have set up a service referred to as a xe2x80x9crelay.xe2x80x9d A relay, as the term is used herein, refers to a system of voice to TDD communication in which an operator, referred to as a xe2x80x9ccall assistant,xe2x80x9d serves as a human intermediary between a hearing user and a deaf person. Normally the call assistant wears a headset that communicates by voice with the hearing user and also has access to a TDD device which can communicate to the deaf user using a TDD appropriate protocol. In normal relay operations in the prior art, the call assistant types at a TDD keyboard the words which are voiced to her by the hearing user and then voices to the hearing user the words that the call assistant sees upon the display of his or her TDD. The call assistant serves, in essence, as an interpreting intermediary between the deaf person and the hearing person to translate from voice to digital electronic forms of communication.
To facilitate and modernize the systems available for providing telecommunication services for the deaf, efforts have been made to both update the techniques for providing assistance to the hearing impaired as well as providing services to users who are modestly hearing impaired but not deaf. In U.S. Pat. No. 5,909,482, a relay is described which uses a re-voicing technique and a speech recognition engine to greatly improved the speed of services provided by a relay. This patent also discloses a small portable device, called a personal interpreter, which make possible providing location independent and instantaneously available interpreting services to the deaf. In U.S. Pat. No. 6,075,842, methods and devices for providing text enhanced telephony are described in which a text stream is provided along with voice in telephone communications with hard of hearing users. The text stream is used to provide the assisted user with a visual representation of the text of what is said by the other person in a communication session, so as to gently assist a person with some hearing deficiency in using the telephone. The full specification of U.S. Pat. Nos. 5,909,482 and 6,075,842, as well of that of each other patent referred to in this document, is incorporated herein by reference.
The present invention is summarized in a method for transmitting voice and text of words over a telephonic connection between a hearing user and an assisted user through a relay, the method including the steps of digitizing the voice of the hearing user; creating a digital text at the relay corresponding to the words spoken by the hearing user; combining the digitized voice and the text into combined digital data packets, each packet including a format character indicating the type of format for that packet, at least some of the digital data packets combining at least one byte of digitized voice data with at least one byte of text representing a character in the text of the words spoken by the hearing user; and transmitting the combined packets to the station of the assisted user over a telephone connection so that the station can reconstitute both voice and text from the digital data packets for the assisted user.
The present invention is also summarized in a communication system using that method to communicate voice and text of the words spoken by the voice to a station used by an assisted user.
The present invention is intended to create a flexible communication protocol, using minimal overhead, which is capable of sending voice and the text for the words spoken by that voice, in digital form over common telephonic communication linkages.
Other objects, advantages and features of the present invention will become apparent from the following specification when taken in conjunction with the accompanying drawings.